Search

3 TABLEIsotopic enrichment between adult killer whales (Orcinus orca) and other analyzed groups (killer whale calves, humpback whale calves and adults, sea turtles, and fish) from the Mexican Central Pacific from 2010 to 2014. The killer whale (KW, I Orcinus orca i ) is the most cosmopolitan species among cetaceans (Bryun, Tosh, & Terauds, 2012; Heyning & Dahlheim, 1988), showing a unique global population genetic structure among nonhuman species (Foote et al., 2019). GLO:KQE/01apr21:mms12748-fig-0002.jpg PHOTO (COLOR): 2 Predatory interactions of killer whales (KW, Orcinus orca) on olive ridley sea turtles (Lepidochelys olivacea) and dolphin species in Mexican Central Pacific waters. [Extracted from the article]

To study the adaptive mechanisms of host and symbiont in a decrease in pH, coral branches ofPocillopora capitatafrom La Boquita reef in the Bay of Santiago, México were assigned to experimental units (n = 38 per treatment) and three pH treatments were evaluated: (a) pH 8.00–8.40 (control; Treatment C1), (b) pH 7.85–7.95 (Treatment C2) and (c) pH 7.60–7.70 (Treatment C3). Corals were collected at the beginning of the experiment (T0) and at different times:T1(5 h),T2(12 h),T3(48 h) andT4(168 h). We examined malondialdehyde (MDA), antioxidant enzyme activities (SOD and CAT), antioxidant capacity and chlorophylla(Chla) content. The results showed a different response to the treatment between zooxanthellae and Cnidaria tissues. Initially in zooxanthellae, we observed a SOD response for the C3treatment; however this response did not prevent lipid degradation. In Cnidaria, the C3resulted in a greater SOD activity from the middle to the end of the experiment. The results improve our understanding of the effects of ocean acidification, the ability of coral to respond to environmental changes and the use of biochemical indicators related to the physiological condition for the recognition of coral communities affected by a decreases in pH. [ABSTRACT FROM PUBLISHER]

Fragments of the coral Pocillopora spp. were collected from Carrizales Reef to assess two transplantation techniques for coral reef restoration: (1) coral clusters (CC) technique, in which five to seven coral fragments were joined using plastic straps, and (2) simple aggregation (SA) technique, in which fragments were placed evenly on the seabed. Over 270 days, the transplanted fragments were monitored for various indicators of coral health, including skeletal growth, the proportion of colonizing invertebrates, coral fragmentation, the proportion of algal growth, signs of coral disease, and the degree of fusion of coral fragments. We found 95.5% and 89.0% survival of fragments with the CC and SA techniques, respectively. These results indicate that the CC technique leads to greater stability, merger and integration of fragments, and greater aggregation of the fragments with the substrate at transplantation sites. Both transplantation methods are economical and could easily be applied at a broad scale for coral reef restoration. [ABSTRACT FROM AUTHOR]

The physiological responses of the coral Pocillopora capitata to environmental conditions common in winter and summer were studied in 2007 during February–March (winter) and June–July (summer) at La Boquita reef (Manzanillo, Colima, Mexico). Shallow and deep sampling stations were established at different distances from a small jetty built next to the Juluapan Lagoon. We analyzed superoxide radicals ( ) and lipid peroxidants (TBARS); the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST); chlorophyll a (Chl a), zooxanthellae density (ZD); and mycosporine-like amino acids (MAAs). Our results showed that the , TBARS, CAT, GST, MAAs, and Chl a, levels were significantly higher in summer (P < 0.05); no seasonal difference was found for GPx, GR or ZD. We found significant differences (P < 0.05) in winter only for Chl a and ZD at shallow sites and, in contrast, for at deeper sites. The results of this study indicate that increasing temperature and radiation associated with seasonal changes (from winter to summer), the efficiency of the enzymes GST, CR and GPX, and the production of MAAs together form a powerful mechanism for P. capitata to offset the detrimental effects of environmental change. [ABSTRACT FROM AUTHOR]

Coral reefs are impacted by a range of environmental variables that affect their growth and survival, the main factors being the high irradiance and temperature fluctuations. Specimens of Pocillopora capitata Verrill 1864 were exposed to photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) for 32h under laboratory conditions. We examined lipid peroxidation (MDA), antioxidant enzyme activities (SOD, CAT, GPx and GST), chlorophyll a (Chl a), carotenoid pigments (CPs), mycosporine-like amino acids (MAAs), and expulsion of zooxanthellae. Our results revealed that corals exposed to UVR had relatively low levels of carotenoids and antioxidant enzyme activities compared to those exposed to PAR, as well as lower CPs/Chl a ratios. Although MAAs and CPs are rapidly produced as non-enzymatic antioxidants in response to UVR in corals, these were not sufficient, even in the dark phase of the experiment, to mitigate the damage caused by formation of reactive oxygen species (ROS), which caused breakdown of the symbiotic relationship between the zooxanthellae and the host animal to an extent 33 times greater than in the PAR treatment. In this study, it could be possible to distinguish that, parallel to the short-term adjustments, such as the amount of pigment in the algae or the sensitivity of the photosynthetic response reported in other species of coral, P. capitata exhibits at the enzymatic level a series of responses oriented to resist the effects derived from the propagation of ROS and, thus, to adapt to and maintain its reproductive capacity in shallow oceanic environments that commonly exhibit high UVR levels. Nevertheless, as a result of the inappropriate location of the artificial intercommunication structure of the Juluapan Lagoon with respect to the arrecifal area of study and therefore of the tides influence, other variables, such as the changes in short-term in turbidity, sediment inputs, nutrients, temperature and osmolarity, can act in combination and cause irreversible damage. The implementation of a management plan for the coralline reefs of the Mexican Pacific coast is required. [ABSTRACT FROM AUTHOR]

Research on olive ridley sea turtle (Lepidochelys olivacea) has emphasized egg-laying females and neonates, using data collected on nesting beaches, but no systematic studies on morphological characteristics by size and sex have been published. This research describes the morphometry of free-living olive ridley sea turtles from coastal and oceanic waters of the Mexican Central Pacific captured and released from 2011 through 2013. A total of 3469 km was surveyed, and 142 sea turtles were evaluated by sex, size class, marine area, and geographic region for nine corporal measurements and their allometric relationships. The average curved carapace length (CCL) was 62.12 cm, range 42-94 cm. Significant differences were found by sex and size class with total tail length (TTL) (♂ = 26.33 cm, ♀ = 12.4 cm); similarly with vent to tail tip length (VTTL) (♂ = 6.38 cm, ♀ = 3.86 cm); and for rear flipper length (RFL) (♂ = 28.17 cm, ♀ = 38.62 cm, immatures = 23.80 cm). Turtles from the coastal region of Colima-Michoacán showed longer CCL = 62.46 cm and wider CW = 66.58 cm. Adult female RFLs showed positive allometry, b = 1.098, suggesting an accelerated growth of the posterior extremities, probably favoring reproductive behaviors, e.g. nest digging and egg-covering. Morphological differences were likely due to ontogenetic sexual distinctions rather than marine area or geographic differences. [ABSTRACT FROM AUTHOR]

It has been established that cryptic fish (CF) contribute to keeping the equilibrium of marine environments, and are also potential indicators of the environment. In the present study, ecological evaluations of CF-associated with reef communities exposed to high or low anthropogenic pressure off the coast of Colima, Mexico (La Boquita-LB, and Carrizales Bay-CA, respectively) were carried out. During 2014 a total of 16 surveys were carried out during winter-spring (WS), and eight surveys were carried out in summer-fall (SF). Three CF surveys were carried out in each reef community, covering a 180 m² area; several ecological indices were calculated, and the benthic habitat was characterized. A total of 3,056 CF belonging to 23 species, 22 genera, and 15 families were recorded. The species Axoclinus lucillae, Acanthemblemaria macrospilus, Coralliozetus boehlkei, Ekemblemaria myersi, and Hippocampus ingens represented new records for CA and LB. The physiographic and topographic characteristics of the marine substrate were factors that significantly influenced the occurrence of CF, especially those with reduced mobility. There was higher CF richness and diversity during the SF. The species A. macrospilus, C. boehlkei, and E. myersi, associated with rocky environments with high sponge and macroalgae cover, were identified as potential bioindicators of degradation of the benthic habitat. The species Cirrhitichtys oxycechalus, A. macrospilus, Coryphopterus urospilus, and Elacatinus punticulatus were associated with coralline, crystalline, and relatively unperturbed environments. [ABSTRACT FROM AUTHOR]

The article discusses the foraging behavior of the rough-toothed dolphin (Steno bredanensis) off southern Jalisco and Colima coasts in the Mexican Central Pacific (MCP). It says that marine surveys on the coastal waters were conducted from January 2010 to December 2013. It mentions the four prey species of rough-toothed dolphins that were identified including the black skipjack tuna (Euthynnus lineatus), the gafftopsail pompano (Trachinotus rhodopus), and the dolphinfish (Coryphaena hippurus).

Little is known about the effects of the interaction of growth hormone (GH) with 17 alpha-methyltestosterone (17-MT) during fish growth. We evaluated this in the present study to assess the effect on fish growth. Fish in two batches of juvenile tilapia (Oreochromis niloticus) (approximately 5.0cm in length) were randomly assigned in triplicate to three treatments and a control group, distributed among 12 fiberglass tanks of 1 000L capacity (50 fish per tank) in an experiment covering a period of six weeks. The experimental groups were: a) fish treated with 17-MT and GH in mineral oil (RGH); b) fish treated with 17-MT and mineral oil without the addition of GH (R); c) fish treated with GH in mineral oil but not 17-MT (NGH); and d) fish of the control group, which were treated with mineral oil but not 17-MT or GH (N). The GH was injected into the fish at a rate of 0.625mg/g body weight. Morphometric data were recorded at the beginning of the experiment (T0) and at 15, 30 and 45 days (T15, T30 and T45), and various indicators of growth were assessed: condition factor (K); survival percentage (S), feed conversion rate (FCR), percentage weight gain (WG) and (v) daily weight gain. The optimum dietary level was calculated assuming 5% food conversion to total weight in each group. During the experiment, the fish were provided with a commercial food containing 45% protein. The data showed that GH injection resulted in a greater weight gain in fish treated with 17-MT (the RGH treatment group), being particularly significant increase in weight during T15 and T30 (p<0.05). High values of K were found in the R and RGH treatments during the initial days of the experiment, which may have been a consequence of the better nutritional status affecting both weight gain and growth in body length, as a result of the additive effects of 17-MT and GH. The fish in groups not treated with 17-MT and treated with 17-MT and added GH showed greater increases in WG per day, higher K values and lower FCRs than fish in the other groups, which suggests that greater feed efficiency occurred in the hormone-treated fish. Fish in the RGH treatment showed the most growth, suggesting a possible interaction between 17-MT and injected GH.